Question

Raul has scraped his knee and noticed that after a week it had almost completely healed. Raul wondered how the skin was able to repair itself while looking exactly the same as his non-injured skin. In 3-5 sentences explain how mitosis plays a role in healing skin after injury and is able to maintain the look of the existing, non-injured skin.

Answer 1

When skin is injured, stem cells and progenitor cells in the basal layer of the epidermis and fibroblasts in the dermis divide by mitosis to replace lost cells. Mitosis produces genetically identical daughter cells that then differentiate into the specific cell types (keratinocytes, fibroblasts, etc.) needed for the skin layers. Those new cells secrete the correct proteins (like keratin and collagen) and follow local chemical signals and scaffolding to take up the right positions and restore tissue architecture. Because the new cells are matched to the original tissue and guided to the proper arrangement, the healed area can closely resemble the surrounding, uninjured skin.